Ebay tend to let you buy a few things before they request this information.

They also tend to only prompt you to provide the information when you want to do something important like bidding on an item you have decided that you want to buy.

I guess they realise that you are far more likely to provide the information in those circumstances... However, it's obviously impossible when the bid is being placed by an automated service like Gixen, and just results in failures of the nature you have just experienced._________________Mark